HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
xnofriendsx

Jetting Recommendations Please - 02 YZ426

3 posts in this topic

Can someone please recommend some jetting specs?

The settings below were decent when i was living at sea level, but i recently moved to 3500ft elevation and just did the BK Mod with .5 sec squirt. It was at around 3 sec squirt. I will be testing it in a few days. I am yet to start it up yet after i did the BK Mod the other day.

Two Questions:

1. What settings below should i change due to the BK Mod?

2. What settings below should i change due to the elevation change?

Thanks for any help.

Model: 2002 YZ426

Timing: YZ

Main Jet: 162 (stock)

Pilot Jet: 42 (stock)

Starter Jet: 72? (stock)

Leak: ?

Fuel Screw: Zip Ty: 1.5 turns out

Air Box: No Lid

Pipe/Muffler: Stock

Altitude: was at sea level, then just moved up to 3500-5500ft

Temp: 30-70F

Humidity: <20%

Share this post


Link to post
Share on other sites

Theoretically, a 4200 ft increase in altitude would require you to lean your jetting by a factor of about .96, which would mean a 155 main and a 40 pilot. (Don't fiddle with the starter jet until there's some proof you need to. Your carb has no leak jet)

However, what I suggest you do is try the bike as is first. YZ426's had a rep for being lean on delivery, and you may find it runs really well just as it is, or perhaps doesn't need as much correction as the charts would indicate.

Share this post


Link to post
Share on other sites

xnofriendsx sorry to hi jack your thread...

grayracer I'm hoping you can help me out with my jetting issues also? I have an '06 YZ450F and I am located in the San Francisco Bay Area. I replaced the jets with the FMF kit. Main jet is 150 and Pilot Jet 48, went 2 turns out on the fuel mixture screw and the have the needle clip at the # 4 groove from the top. The problem I am experiencing is it still backfires when I let off the throttle and sometimes doesn't idle that good. Any suggestions? Thanks for the help!

-Dez

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0